Here’s an unfortunate allergy! While sex can be good for you (in many ways), it turns out that even brushing your teeth or waiting hours after eating may not prevent some partners of people with food and medicine allergies from triggering an allergic reaction through a kiss. "Kissing" allergies are most commonly found in people who have food or medication allergies. Symptoms include swelling of the lips or throat, rash, hives, itching and wheezing.
Why do lovers kiss? One reason may be that the exchange of saliva increases our sex drive, which may be why men seem to prefer FRENCH kissing!
In LiveScience.com, Robin Lloyd quotes anthropologist Helen Fisher as saying, “There is evidence that saliva has testosterone in it. And there is evidence that men like sloppier kisses with more open mouth. That suggests they are unconsciously trying to transfer testosterone to stimulate sex drive in women.”
More than 90% of human societies kiss, and so do pygmy chimpanzees and bonobos. Foxes lick each others’ faces, birds tap their bills together, elephants put their trunks into each another’s mouths.